| NSF Org: |
SES Division of Social and Economic Sciences |
| Recipient: |
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| Initial Amendment Date: | March 27, 2013 |
| Latest Amendment Date: | March 27, 2013 |
| Award Number: | 1260777 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Jonathan Leland
SES Division of Social and Economic Sciences SBE Directorate for Social, Behavioral and Economic Sciences |
| Start Date: | March 15, 2013 |
| End Date: | February 28, 2015 (Estimated) |
| Total Intended Award Amount: | $49,150.00 |
| Total Awarded Amount to Date: | $49,150.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
438 ACADEMY ST BOONE NC US 28608-0001 (828)262-7459 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
POB 32068 Boone NC US 28608-2068 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Decision, Risk & Mgmt Sci |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.075 |
ABSTRACT
This project focuses on a phenomenon of quantitative cognition called sample size bias, which occurs when people make judgments of averages. Specifically, as the number of items in a set increases, people judge the average to be greater. For example, the average of a set of ten numbers is judged to be greater than the average of five numbers -- even when the two sets have the same average. But sample size bias also occurs for conceptual dimensions such as risk. For example, the average heart-attack risk of ten people is judged to be greater than the average heart-attack risk of five people. The core of this project is a series of empirical studies in which a cross-section of people judge several kinds of averages under a variety of conditions. These studies have two purposes. The first is to test a theory that assumes that set size automatically activates an analog representation of magnitude in the brain, which in turn affects the representation and judgment of the average. The second is to see whether the sample size bias affects other kinds of judgments about averages, including judgments about one's own experience and behavior.
This work is important for a number of reasons. First, the theory being tested has the potential to help integrate sample size bias with similar phenomena from distinct areas of research including judgment and decision making, perception, and the neuroscience of quantitative cognition. Second, this research will help identify real-world contexts in which people's judgments of averages are likely to reflect sample size bias. For example, surveys often ask people to make judgments about what is average or typical for them or their peers (e.g., the average number of times they use health services per year). It is important to know whether such judgments are likely to be systematically biased and how such biases might be corrected. Finally, this project will provide high quality research training and experience to a diverse group of undergraduate and master's-level students at California State University, Fresno and Appalachian State University. This in turn will prepare them to succeed in doctoral studies in any of a variety of areas, cognitive and social psychology, judgment and decision making, and management science.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The research conducted under this award investigated people making judgments about the averages of items. Based on our previous research, we predicted that participants' estimates would increase as the number of items they were averaging across increased. In other words, people would exhibit a sample size bias. For example, in one of the studies conducted under this award, participants performed a number of tasks and were asked to estimate how long, on average, each task took. We found that participants who were asked to think about the last 10 tasks gave longer duration estimates than participants who were asked to think about the last 2 tasks.
One of the primary goals of our research was to identify different contexts where we might find a sample size bias. Previous studies demonstrated the bias when people made estimates of groups of other people and when making estimates of groups of numbers. Our current studies established that people exhibit a sample size when making judgments of the size of sets of objects and when estimating the average duration of numerous items. A second goal of our research was to establish why people exhibit the sample size bias. While we have not identified the specific cause, our studies have ruled out a number of potential explanations. Furthermore, because we have been able to demonstrate the sample size bias is so many different situations, it seems likely that it is caused by a general underlying process. For example, Walsh (2003) proposed A Theory of Magnitude framework that suggests that people have a generalized magnitude system. People use this abstract magnitude representation when making judgments about items across numerous dimensions (e.g., space, size, time, quantity). It is possible that the number of items in a group influences people’s general representations magnitude. Then, when making other judgments (e.g., the average duration of a group), people give judgments that are influenced not only by the average duration, but also the number of items in the group (because both have influenced people's representations of magnitude).
In addition to the intellectual merits of the research, we also had numerous broader goals. Specifically, the research helped to partially fund numerous undergraduate and graduate students as they pursued their degrees. These students gained valuable research experience that helped them become competitive applicants as they applied for future academic positions. Perhaps more importantly, these students learned more about scientific research and critical thinking skills that will help them in a wide variety of contexts.
Last Modified: 05/14/2015
Modified by: Andrew Smith
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